A police spokesman said: “At 1.42pm on Wednesday (May 30) police were called to Stagelands at Langley Green, Crawley, where a pedestrian, a 15-year-old boy from East Grinstead, was thought to have collapsed after suffering a medical episode, possibly brushing against a passing bus as he did so.

“The Kent,Surrey and Sussex air ambulance was called in and the boy was flown to St George’s Hospital in Tooting, London, where he is currently being treated for head injuries.

“The bus at the scene was driven by a 66-year-old man from Peacehaven, who was unhurt.”